1 00:00:00,299 --> 00:00:05,130 As the pandemic continues - variants have become the latest concern 2 00:00:05,130 --> 00:00:07,823 with notable examples detected in South Africa, 3 00:00:07,823 --> 00:00:10,320 Brazil and the UK. 4 00:00:10,320 --> 00:00:12,943 But variants are complicated. 5 00:00:12,943 --> 00:00:15,735 Each one is made up of a collection of mutations, 6 00:00:15,735 --> 00:00:22,379 all of which have the potential to change the SARS-CoV-2 virus in unexpected ways. 7 00:00:22,379 --> 00:00:26,030 So what do scientists mean when they talk about variants 8 00:00:26,030 --> 00:00:29,735 and what might this mean for the future of the pandemic? 9 00:00:30,854 --> 00:00:34,828 Viruses multiply by copying their genomes over and over. 10 00:00:34,828 --> 00:00:38,953 But like an old photocopier, these copies aren’t always perfect. 11 00:00:38,953 --> 00:00:42,996 Each of these imperfect copies is a variant. 12 00:00:43,120 --> 00:00:47,376 Normally the imperfections or mutations don’t change how the virus behaves 13 00:00:47,376 --> 00:00:51,780 e podem torná-los menos eficazes do que a cepa original. 14 00:00:51,780 --> 00:00:56,431 Mas, raramente, as mutações podem alterar o vírus de algumas formas importantes. 15 00:00:56,431 --> 00:01:03,199 Ele pode se tornar mais infeccioso, ou mais capaz de evitar o sistema imune. 16 00:01:03,199 --> 00:01:06,000 Quanto mais um vírus consegue se replicar sem controle, 17 00:01:06,000 --> 00:01:10,680 mais chances ele tem de acumular essas raras mutações benéficas. 18 00:01:10,680 --> 00:01:15,871 Isso pode ocorrer quando o vírus consegue se espalhar rápido em uma população 19 00:01:15,871 --> 00:01:18,554 ou se encontram um hospedeiro menos capaz de combatê-lo, 20 00:01:18,554 --> 00:01:24,417 como alguém com sistema imune comprometido por tratamentos ou portadores de HIV+. 21 00:01:24,417 --> 00:01:28,646 Se um conjunto de mutações torna uma variante mais bem sucedida, 22 00:01:28,646 --> 00:01:33,757 ela pode ficar mais proeminente, e é aí que ela é notada. 23 00:01:33,757 --> 00:01:37,803 Epidemiologistas podem até rotulá-la como uma 'variante preocupante', 24 00:01:37,803 --> 00:01:42,330 como as encontradas no Brasil, África do Sul e Reino Unido. 25 00:01:42,330 --> 00:01:48,060 Há meses, cientistas tentam descobrir o que alterou essas variantes 26 00:01:48,060 --> 00:01:50,060 e o que essas alterações significam. 27 00:01:50,060 --> 00:01:56,180 Uma variante se propagando não quer dizer que ela tenha uma mutação vantajosa. 28 00:01:56,180 --> 00:02:01,320 Por exemplo, um pequeno grupo de pessoas pode mover a variante de uma região 29 00:02:01,320 --> 00:02:06,310 para outra, como turistas de férias, voltando de lugares populares. 30 00:02:06,310 --> 00:02:09,592 Isso pode fazer com que a variante se propague em um novo local, 31 00:02:09,592 --> 00:02:13,794 apesar de não haver alterações significantes na biologia do vírus. 32 00:02:13,794 --> 00:02:17,200 Isso se chama 'Efeito Fundador'. 33 00:02:17,200 --> 00:02:21,828 Entender por que uma variante surgiu requer uma combinação de estudos. 34 00:02:21,828 --> 00:02:25,379 A epidemiologia ajuda a detectar e rastrear novas variantes 35 00:02:25,379 --> 00:02:28,939 e sinalizar padrões de infecção novos ou preocupantes . 36 00:02:28,939 --> 00:02:31,606 Enquanto isso, exames laboratoriais podem identificar 37 00:02:31,606 --> 00:02:35,666 como as mutações estão alterando as propriedades do vírus. 38 00:02:35,666 --> 00:02:39,063 Estes estudos estão começando a identificar as mutações 39 00:02:39,063 --> 00:02:42,043 que controlam o vírus. 40 00:02:42,043 --> 00:02:46,940 Algumas variantes se propagam mais rápido, e há indícios de que algumas mutações 41 00:02:46,940 --> 00:02:52,510 podem enfraquecer ou até ignorar a imunidade natural ou derivada da vacina. 42 00:02:52,510 --> 00:02:58,470 Por exemplo, a mutação D614G, conhecida por virologistas como Doug, se propagou 43 00:02:58,470 --> 00:03:02,290 no início da pandemia e é presente em quase todas as variantes. 44 00:03:02,290 --> 00:03:08,440 It affects the spike protein that coronavirus particles use to penetrate cells. A mutation 45 00:03:08,440 --> 00:03:11,246 in the genome changes one amino acid for another, 46 00:03:11,246 --> 00:03:17,409 and makes the new variant more infectious than the original virus. 47 00:03:17,409 --> 00:03:25,658 N501Y also known as Nelly, is another spike protein mutation which appears to be associated with increased transmissibility. 48 00:03:25,658 --> 00:03:34,599 This mutation has been detected in the B.1.1.7, B.1.351 and P.1 strains - all variants of concern. 49 00:03:34,599 --> 00:03:43,610 The worry of so-called ‘immune escape’ has also been hinted at with another spike protein mutation, E484K or Eek. 50 00:03:43,610 --> 00:03:51,270 Eek has been spotted in B.1.351 and P.1, the variants detected in South Africa and Brazil. 51 00:03:51,270 --> 00:03:57,960 Lab studies in early in 2021 showed that the variant could evade some virus-blocking antibodies, 52 00:03:57,960 --> 00:04:04,590 while trials in South Africa suggested that the variant reduced the efficacy of several vaccines. 53 00:04:04,590 --> 00:04:09,820 Despite these worries, the coronavirus is actually mutating very slowly compared to 54 00:04:09,820 --> 00:04:16,699 something like influenza and it seems like the vaccines developed so far will remain at least partly effective. 55 00:04:16,699 --> 00:04:21,774 But scientists are still taking the threat posed by variants seriously. 56 00:04:21,774 --> 00:04:25,639 And there are several things that can be done to help tackle it. 57 00:04:25,639 --> 00:04:30,000 Firstly, to do anything researchers need data 58 00:04:30,000 --> 00:04:37,169 - it’s very important to monitor and trace the emergence of variants and that isn’t always simple to do. 59 00:04:37,169 --> 00:04:41,668 Organisations like the COVID-19 Genomics UK consortium, or COG-UK, 60 00:04:41,668 --> 00:04:47,527 have stepped up their efforts to combine fast sequencing with efficient data sharing. 61 00:04:47,527 --> 00:04:53,330 COG-UK has already sequenced over 400,000 SARS-CoV-2 genomes. 62 00:04:53,330 --> 00:04:58,910 Next, researchers need to look forward to how these mutated viruses could affect global 63 00:04:58,910 --> 00:05:06,617 vaccination efforts. Existing vaccines can be redesigned and combinations of vaccines are also being tested 64 00:05:06,617 --> 00:05:14,290 but it could be difficult to perform reliable clinical trials amid the ongoing vaccination programmes. 65 00:05:14,290 --> 00:05:18,497 Right now though, work needs to continue at a national level. 66 00:05:18,497 --> 00:05:23,654 Public health policies such as track and trace, social distancing and vaccine roll-outs 67 00:05:23,654 --> 00:05:30,849 are powerful tools to interrupt transmission and keep tabs on new variants. 68 00:05:30,849 --> 00:05:34,441 After all, every time the virus is prevented from spreading, 69 00:05:34,441 --> 00:05:36,986 it's also prevented from mutating, 70 00:05:36,986 --> 00:05:41,525 nipping new variants in the bud before they even have a chance to develop.